Detect if the Telemeter is available

Telenet sometimes perform updates to the 'Mijn Telenet' portal. It would be useful to detect such events. It could be done by checking if the login page has the username/password form, since they remove the form when maintenance is going on. They also give you a date when it will be available again.

It would be nice to notify the user that 'Mijn Telenet' is offline, as well as the expected date & time when it will be available again.